1. Field of the Invention
The present invention relates to mechanically operated Multi-Interval Timers, specifically to timing pins used to control multiple, sequential intervals.
2. Description of the Prior Art
Reference is made to the single interval pins used in the first Multi-Timer, U.S. Pat. No. 3,187,319, in order that the new invention, the PROGRAMMED MULTI-TIME INTERVAL PIN, may be completely understood and appreciated in the proper context. FIGS. 1 & 2 show the features of the Multi-Timer. The unit contains a motor which drives a timer disc 30 counterclockwise, in two hour continuous cycles. The disc 30 has a circle of 120 disc holes 32, evenly spaced one minute apart, around the 360 degree periphery. A disk hole 32 has a rotary speed of 3 degrees per minute. The timer disc 30 rotates over a clock face numbered clockwise in the same one minute intervals, beginning with zero at the top of the face and ending at 120 minutes (2 hrs.), also the zero unit. A single interval pin 34 inserted into one of these disc holes 32 to select a desired time increment, sixty minutes for example, requires 60 minutes to count down to zero. If the single interval pin 34 is not removed, a new 2 hour timing increment begins with the next one-minute space. That means, each minute a 120 minute countdown ends and a new one begins. As a result, there are always 120 individual disc holes 32 available, in a descending order of value, for selection.
The single interval pin 34 was designed in a tear drop shape, with the pin molded into the plastic at the narrow end, so that it would occupy just one disc hole 32 space, leaving adjacent holes available to other single interval pins 34. The broader opposite end is flattened to provide space for the code numbers. FIGS. 1 & 2 illustrate this original system.
Multi-Timer Pins are single interval pins used to select any time interval up to two hours, in one minute intervals. There are four sets of five pins, numbered from 1 to 5. Each set is color coded red, yellow, blue or green. These pins reside in a Monitor Panel that is divided into four sections with five subsections, each coded and numbered to correspond with the resident pin. The function of this panel is to correlate the pin with an instruction temporarily written on a white space adjacent to the resident pin. For operations routinely performed, the notation can remain, which temporarily reserves that pin and space. Refer to FIG. 1, which illustrates this description.
The first model under this patent was produced by Coulter Electronics, Inc.. The instructions for its used are as follows.
1. PROGRAM for a SINGLE TEST, or a single group of tests, using a single pin for a SINGLE TIME INTERVAL, follows the basic Monitor Panel Program described above. A single color coded, numbered pin selects a time interval which correlates with the instructions written in the similarly coded section on the panel.
2. PROGRAM for monitoring a SINGLE TEST which is started at variable short intervals, but all requiring the SAME TIME INTERVAL, as with the ESR (Sed. Rate) must use a single pin to represent the starting time of each patient. The Monitor Panel provides a black coded section of pins, sequentially numbered, each number to represent one patients selected starting time. The pin color identifies the test, each pin selects the same 1 hr. time interval when inserted and the pin number identifies the patient.
3. PROGRAM for monitoring a SINGLE TEST requiring MULTIPLE TIME INTERVALS, as with the OGTT, one color coded section of the Monitor Panel is assigned to each patient. The timing intervals are written in the five numbered subsections adjacent to each pin. The pin code numbers indicate the sample sequence. When each pin is inserted into the timing disc, the selected time interval is the one indicated on the panel. The pin color identifies the patient, the pin number refers to the sampling sequence and also refers back to the noted sampling time on the panel.
This invention is intended to address the problems discussed in the following statements. It is also intended to embrace any important elements mentioned.
The diagnostic significance of an oral glucose tolerance curve is dependent on the control of the many variables present in the collection of the timed, sequential blood samples that represent the patient's glucose level at each sample point. These variables are listed in order of occurrence.
1. Fasting state of patient should be verified.
2. Loading glucose dose should be drunk within 5 minutes, and the time finished and amount taken recorded (scale on bottle).
3. Time sample drawn must be recorded.
4. Rigid control of the accuracy of the sequential sample intervals.
Many patients have difficulty drinking the glucose solution and take a long time to finish. In our laboratory, patients are encouraged to finish within 5 minutes, however the additional time required after the sequential timing begins is recorded and the amount of glucose drank (scale on bottle) must be documented.
The time intervals need to be accurately controlled since the interpretation of the glucose tolerance curve is based on the blood glucose level at each specified sample interval from which the curve is made. The inevitable and variable time delays inherent with the venipuncture technique of collecting blood samples should be documented, so that the curve can be corrected. This correction is accomplished with both systems in different ways, The Programmed Multi-Time Interval pin can start the next interval, while counting down the last interval; the Single Interval Pin cannot.
The accuracy of the corrected curve is dependent upon the accuracy of the specified sample intervals. The single pin system is inadequate and in many instances, unable to provide integrated sample points. The Programmed Multi-Time Interval Pin, the present invention, is designed so that all the timed sample points are locked in simultaneously at the start of the test. Automatically the sample points are all sequentially related and all refer to the same starting point.
The patient preparation for venipuncture varies and the actual execution is unpredictable. The patients with tiny, deep veins are the most difficult, the difficulty increasing with each subsequent sample. The average time for this procedure is five minutes; with difficult veins, it can be ten minutes or more. The blood glucose level is rising as the patient absorbs the glucose dose and the initial blood samples are tracking this rise in order to establish the peak level. The rest of the samples are establishing their pattern and the rate of the fall to the initial level. Therefore, the blood glucose levels at the specified sample points are critical to the diagnostic interpretation of the curve. The resultant erratic pattern, inevitable in the collection of the blood samples, could significantly influence the interpretation of the curve. Therefore, making a note of this additional time at the completion of each collection, and using that information to construct a corrected curve, is mandatory for accurate results. The corrected curve is compromised unless the integrity of the time increments of the basic curve is rigidly controlled.